This application is related to U.S. Pat. No. 3,798,615 by the same inventor and assigned to the same assignee as this application. The material therein is hereby incorporated by reference.
1. Field of the Invention
This invention relates to microprocessors. A microprocessor is a device capable of performing arithmetic, logical, and decision making operations under the control of a set of stored instructions, but of small size, capable of being manufactured on a few (not more than four) integrated circuits. The instructions are stored either temporarily or permanently in some type of memory device. The microprocessor is capable of communicating with a set of peripheral devices by means of some well defined bidirectional structure. The operation of a microprocessor is often slow when compared to large computing devices, but it has the advantage of being implementable on one integrated circuit chip and of being relatively inexpensive.
2. Description of the Prior Art
Large scale integration techniques have made it possible to produce in a small space, logic circuits which formerly required thousands of discrete devices. When data processing and electronic computer systems are reduced to a few LSI circuits, the organization is usually a scaled down version of a large scale data processing system. One of the problems encountered when putting a data processing system on a few integrated circuits is the limitation on the number of external connections that can be made to the integrated circuit.
The invention disclosed is a microprocessor organization that is suitable for implementation on a single integrated circuit requiring a minimum of external connections consistent with an acceptable operating speed.